1. Field of the Invention
The invention relates to a machine for fitting and removing a tire from a rim of a wheel, comprising a frame, a table capable of having the rim attached thereto and of rotating said rim in a centered manner about an axis (Y) and a lever articulated on the frame, said lever comprising a control point (A), a pressure element designed to exert a pressure on a bead and/or a wall of the tire at a working point (B) of the tire, a first articulation about a point (C) in order to bring the pressure element closer to or further from the axis (Y), and a second articulation about a point (E) in order to bring the pressure element closer to or further from a central plane perpendicular to the axis (Y) and passing through a center (D) of the rim.
2. Prior Art
Such machines have been known for a long time and make it possible to fit and/or remove a tire from a rim, for example of a wheel of a motor vehicle or a truck or of a motorcycle. To carry out this operation, the wheel is first attached to the table so that its axis coincides with the axis of rotation (Y) of the table. A tool for fitting/removing the tire is then brought over the rim in order to position it close to an edge of the rim. The user then removes and/or fits the tire in a known manner.
During the operation for fitting or removing the tire, it is known that it is appropriate to keep the bead of the tire in a circumferential recess of the rim in order to be able to have said bead pass over the edge of the rim at the fitting/removal tool.
In order to keep the bead of the tire in this position, patent EP 909667 discloses such a machine comprising a lever that is articulated and actuated by an operator. The operator begins by bringing the pressure element into its working position (B) on the wall or on the bead of the tire. Then, by actuating the lever, the operator can push and keep the bead of the tire in the circumferential recess of the rim during the operation for fitting or removing the tire.
Patent EP 909667 also discloses that the lever allows the operator—during a removal operation and after having taken the top bead of the tire out of the rim—to make the bottom bead of the tire (and therefore the tire) rise to the top edge of the rim by placing the pressure element under the bottom wall of the tire and by pulling the lever up.
Although such known devices operate well, the operator must however exert a certain force on the lever so that the pressure element is held at its working point and/or so that it exerts its effect on the tire during the operation for fitting or removing the tire.